The invention relates to an exercise device having a frame consisting of four pivotably interconnected parts. The lower frame part is mounted via a joint between its front and rear end, and the front frame part is pivotably connected to a stand. The upper frame part carries a saddle and the front frame part carries bundles. Pedals are attached to the lower frame, and the movement of one frame part in relation to another frame part or the stand is transferrable via a connecting rod and a crank to a drive wheel pivotably connected to the frame, thus driving a fly-wheel by way of transmission.
Such a device has been described in applicant's U.S. Pat. No. 4,371,185 and also in Applicant's German Patent Application No. P 31 13 242.
All devices of this kind known up to now have the disadvantage of forming different rotating angles of the drive wheel during the two phases of the reciprocal up and down movement of the frame. Because the frame consists of four joints, the different rotating angles of the drive wheel lead to different, physiologically disadvantageous accelerations of saddle, handles and pedals.
The different rotating angles of the drive wheel which occur during the two phases of movement result from the fact that the rotating movement of the lower frame part leads to a relative movement of the crankshaft bearing in relation to the stationary connecting rod bearing.
Another disadvantage of current devices of this kind is the fact that there is no possibility of integrating all rotating and swinging parts of the gear, especially connecting rod and cranks, into the gear casing in order to protect the user of the device against injuries.